I have an 83 Trans Am with the anus of all gm's engines(LG4 305), but I just bought an LT1 that I was told was from a 95 Camaro, when I got there I knew it wasnt but then he said if was from a 95 Caprice, which sounded right since it had iron heads. I looked it over and the plugs looked good, oil good, and the casting numbers checked out as 94-96 5.7 LT1. So I went ahead and bought it. It had no accessories or even the bracket. But it did have the water pump and opti still intact so thats a good thing. Anyway let me get away from the gibberish.

I decided to verify exactly what I had before I start anything on the engine since I wanted to tear it down and at least check it out good, and at the least put new bearings in. So I was trying to find out the exact model year and figured I could do that with the ecm. I got the numbers and did some research and sure enough the guy didnt even know what he had. Turns out the setup is from a 96 OBDII Caprice. Now I have no frickin clue where to go from here. I was counting on OBDI so it would be easy to install and run and such, but with the OBDII I have no idea what to do. So should I sell the OBDII pcm and harness and start looking for an obd 1 setup, or would I be better off adapting the obd 2 system to my swap. I wont have any emissions, no trans sensors since its gonna be hooked to a T5(for now,t56 later), and basically just the bare minimum to make it operate properly. Also does anyone know where I could get a diagram of the OBDII 1996 LT1 harness so I can figure out exactly where everything goes. And how can I bypass all the stuff I cant use or wont be using? I thought about buying a new harness and a used obd 1 computer but the prices are just insane. And I dont even know if I can use an obd1 harness on the engine since it was made for obdII ?

I need to get this situation sorted out asap, since my car is just sitting due to major engine problems, and I am needing to get the LT1 dropped in and drivable.

i hate to do it because its just stupid and makes little sense but I am almost to the point I am gonna have to buy a carb intake for the engine just so I can get it running. But I'd hate to do that to an LT1. If that were my plan I woulda just got a gen 1 sbc. why have an lt1 if your gonna carb it...lol

sorry for the long post, but I am just frustrated, and needing some really good and sound advice. I need to get through this the cheapest I possibly can. I have about 1500 dollars left to take care of all the small stuff, and still have to buy the acc. bracket, all the accessories, mounts, intake ducting, fuel pump, MAF(maybe, hoping to avoid it), and just a crap load of other misc. little bs that always seems to pop up while doing a swap, especially from a carbed non-cc to a late model fuel injected setup.

 

You don't have to worry about the OBDI-OBDII with the LT1's, only difference between the two are, the two extra O2 sensors and the crank sensor, everything else is the exact same. You can get a stock '95 LT1 wiring and PCM and it will plug right in. OBDI will give you better, less expensive ways of tuning since the software is cheaper than say LT1edit, or HPTuners.

Only bad thing I see is you're going to put this motor in front of a T5...expect to replace the transmission in about a month if you bang on it since the T5's behind the 305's are very very weak and possible that even normal driving with a motor with almost twice the HP and torque could destroy it.

Motor mounts, same as the 305 mounts, no cost there
Fuel pump, you may want to consider finding a TPI car in a boneyard and getting all of the fuel lines because they come up the driver side of the car instead of the passenger like a carb car does.
Intake ducting, you can always find LT1 elbows on e-bay cheap.

I would say look on e-bay for alot of it, I also have a phone number of a shop in Cleveland Tn that parts out 4th gens and may have alot of what you're looking for, if you want it send me a PM and I'll get the number to you.

 

I got some pics today of the engine harness and the one plug that i have no clue what goes to. If anyone can tell me what all the connectors are for I'd truly appreciate it. I REALLY wish I knew where to find a diagram of the harness.

 

please tell me what the heck this big connector is?

 

Wow, the impala harness is totally different than the F-body one. I'm gonna take a stab and say that the second picture the big grey connector is the bulkhead connector. The white plug looks like the C230 connector the grey one in the first picture looks like an O2 plug.

 

I have found this site to be very helpful...

http://shbox.com/1/4th_gen_tech1.html

 

I just bought an OBD1 ecm for 94-95, so I just took care of the ecm problem. I figure it isnt significant, but on the sale add for the ecm I bought it said the ecm was a "9C1" ecm. What does that mean? Is that a good thing?

 

9C1 is the police package on the Caprice.

 

Only thing about this, it's for 4th gen, doesn't have anything for the B-body cars.

 

That big connector with the metal 'lock' is part of the ABS system. It's all integrated in these harnesses. The big one with the wires clipped was part of the harness that went to the IP connector (instrument panel). Alot of those you won't use unless you really want to, (oil change light, some other misc stuff, you would need your own little panel made to use those lights).

Like was mentioned above, the OBDI to OBDII swap is straightforward. You can search on it on B-body and F-boy sites that use the LT1 engine. Stick the '8051 ecm in the connectors, remove a couple things, and it works.

now, as far as integration into your '83, if it was me, (I hate extra crap lying around), I would grab a set of schematics, and strip out all the unneccesary wiring in that harness. I have OBDI schematics for F-body and B-body, I think, shoot me a PM with your email address and I'll send them to you. All the connectors that are in question could be traced back to the ecm, and the schematics will tell you if you need 'em or if they become part of the scrap pile.

I normally take a harness, and lay it out on a big table, and strip off all the looming and tape, and label stuff, and use some short wraps of new tape to hold the harness is rough shape (to cheap to use tie-wraps only to cut them off again). As wires get clipped out (or chunks of harness 'fall' out from not being used), the harness gets nice and small. Then retape and re-loom as necessary. You don't have to worry too much, GM made most of the stuff very nice in that most things only plug into one place.

the stupid B-body harness went under the 'homeplate' air intake, so it runs across the manifold. I re-arranged the harness in my brothers car to route around behind, had to lengthen a couple of wires.

otherwise, just clean it up, they sure do get ugly after running awhile, don't they....

 

Oh, one more thing, I hope that you got the fuse block with all the relays, it really makes the installation a drop in if you don't have to rewire all that stuff.....its not hard, its just a pain, since you basically get to re-do what was already a nice compact panel (mounts on passenger side inner fender). If you did get that, I would re-use a caprice main battery cable, it bolts right to the fuse block. weird octopus looking thing, with multiple outputs on it for the starter, fuse block, etc.

 

If this is the fuse block your referring to, then yes, i got it, and thank god it wasnt all hacked up.